Submission #1261484

#	Time	Username	Problem	Language	Result	Execution time	Memory
1261484		kikitop1gg	Fire (BOI24_fire)	C++17	61 / 100	1140 ms	102976 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vi vector<ll>
#define vvi vector<vector<ll>>
#define vs vector<string>
#define vc vector<char>
#define vb vector<bool>
#define vp vector<pair<ll, ll>>
#define vpp vector<pair<ll, pair<ll, ll>>>
#define pp pair<ll, ll>
#define qi queue<ll>
#define qp queue<pp>
#define pqi priority_queue<ll>
#define pqp priority_queue<pp>
#define mi map<ll, ll>
#define mpi map<pp, ll>
#define mip map<ll, pp>
#define mp map<pp, pp>
#define mb map<ll, bool>
#define si set<ll>
#define sp set<pp>
#define sc set<char>
#define mod 1000000007
#define inf INT_MAX
#define all(x) (x).begin(), (x).end()

pp get_max(ll l, ll r, ll k, ll a, ll b, vp& tree) {
    if(r < a || b < l) return {-1, -1};
    if(a <= l && r <= b) return tree[k];
    ll d = (l + r) / 2;
    pp ans1 = get_max(l, d, 2 * k, a, b, tree);
    pp ans2 = get_max(d + 1, r, 2 * k + 1, a, b, tree);
    if(ans1.first >= ans2.first) return ans1;
    return ans2;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    ll n, m;
    cin >> n >> m;
    vp a(n);
    si times;
    for(int i = 0; i < n; i++) {
        cin >> a[i].first >> a[i].second;
        if(a[i].first > a[i].second) {
            a[i].second += m;
        }
        times.insert(a[i].first);
        times.insert(a[i].second);
    }
    vi coor2;
    mi coor;
    for(auto time : times) {
        coor[time] = coor2.size();
        coor2.push_back(time);
    }

    ll size = pow(2, ceil(log2(int(times.size()))));
    vp tree(size * 2, {-1, -1});
    for(int i = 0; i < n; i++) {
        ll start = coor[a[i].first];
        ll end = coor[a[i].second];
        tree[start + size] = {end, i};
    }
    for(int i = size - 1; i > 0; i--) {
        if(tree[i * 2].first >= tree[i * 2 + 1].first) {
            tree[i] = tree[i * 2];
        }
        else {
            tree[i] = tree[i * 2 + 1];
        }
    }


    ll lg = 1;
    while((1 << lg) <= n) lg++;
    vvi up(n, vi(lg, -1));
    for(int i = 0; i < n; i++) {
        auto[start, end] = a[i];
        ll l = coor[start], r = coor[end];
        auto[mx, ind] = get_max(0, size - 1, 1, l, r, tree);
        if(mx <= r) ind = -1;
        up[i][0] = ind;
    }
    for(int k = 1; k < lg; k++) {
        for(int i = 0; i < n; i++) {
            ll par = up[i][k - 1];
            if(par == -1) up[i][k] = -1;
            else up[i][k] = up[par][k - 1];
        }
    }

    ll ans = inf;
    for(int i = 0; i < n; i++) {
        ll cur = inf;
        ll l = 1, r = n;
        while(l <= r) {
            ll v = i;
            ll d = (l + r) / 2;
            for(int k = lg - 1; k >= 0; k--) {
                if(d & (1 << k)) {
                    v = up[v][k];
                }
                if(v == -1) break;
            }
            if(v == -1) {
                r = d - 1;
                continue;
            }
            ll start = a[i].first;
            ll end = a[v].second;
            if(start + m <= end) {
                cur = min(cur, d + 1);
                r = d - 1;
            }
            else {
                l = d + 1;
            }
        }
        ans = min(ans, cur);
    }


    if(ans == inf) ans = -1;
    cout << ans << '\n';
    return 0;
}
/*
4 100
11 30
0 9
9 0
4 5

2
*/

• Subtask 1: 14 / 14
• Subtask 2: 17 / 17
• Subtask 3: 9 / 9
• Subtask 4: 0 / 13
• Subtask 5: 21 / 21
• Subtask 6: 0 / 26